U.S. patent number 9,810,482 [Application Number 14/445,531] was granted by the patent office on 2017-11-07 for inline melt control via rf power.
This patent grant is currently assigned to Apple Inc., Crucible Intellectual Property, LLC. The grantee listed for this patent is Apple Inc., Crucible Intellectual Property, LLC. Invention is credited to Sean O'Keeffe, Joseph C. Poole, Christopher D. Prest, Matthew S. Scott, Joseph Stevick, Dermot J. Stratton, Theodore A. Waniuk.
United States Patent |
9,810,482 |
Waniuk , et al. |
November 7, 2017 |
Inline melt control via RF power
Abstract
Various embodiments provide apparatus and methods for melting
materials and for containing the molten materials within melt zone
during melting. Exemplary apparatus may include a vessel configured
to receive a material for melting therein; a load induction coil
positioned adjacent to the vessel to melt the material therein; and
a containment induction coil positioned in line with the load
induction coil. The material in the vessel can be heated by
operating the load induction coil at a first RF frequency to form a
molten material. The containment induction coil can be operated at
a second RF frequency to contain the molten material within the
load induction coil. Once the desired temperature is achieved and
maintained for the molten material, operation of the containment
induction coil can be stopped and the molten material can be
ejected from the vessel into a mold through an ejection path.
Inventors: |
Waniuk; Theodore A. (Lake
Forest, CA), Stevick; Joseph (Olympia, WA), O'Keeffe;
Sean (Tustin, CA), Stratton; Dermot J. (San Francisco,
CA), Poole; Joseph C. (San Francisco, CA), Scott; Matthew
S. (San Jose, CA), Prest; Christopher D. (San Francisco,
CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc.
Crucible Intellectual Property, LLC |
Cupertino
Rancho Santa Margarita |
CA
CA |
US
US |
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Assignee: |
Apple Inc. (Cupertino, CA)
Crucible Intellectual Property, LLC (Rancho Santa Margarita,
CA)
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Family
ID: |
50446575 |
Appl.
No.: |
14/445,531 |
Filed: |
July 29, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140332176 A1 |
Nov 13, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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13651654 |
Oct 15, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22D
27/04 (20130101); H05B 6/44 (20130101); B22D
25/06 (20130101); C22C 45/00 (20130101); B22D
17/10 (20130101); H05B 6/36 (20130101); B22D
17/04 (20130101); C22C 45/003 (20130101); H05B
6/30 (20130101); B22D 18/06 (20130101); B22D
17/2038 (20130101); B22D 37/00 (20130101); C22C
45/02 (20130101); F27D 3/0025 (20130101); B22D
41/01 (20130101); H05B 6/067 (20130101); C22C
45/10 (20130101); F27D 11/12 (20130101); H05B
6/367 (20130101); C22C 45/008 (20130101); F27D
11/06 (20130101); B22D 27/20 (20130101); F27D
3/14 (20130101); Y02P 10/25 (20151101); Y02P
10/253 (20151101) |
Current International
Class: |
B22D
17/20 (20060101); B22D 17/10 (20060101); H05B
6/30 (20060101); H05B 6/06 (20060101); F27D
3/14 (20060101); F27D 11/12 (20060101); F27D
3/00 (20060101); C22C 45/02 (20060101); H05B
6/44 (20060101); B22D 17/04 (20060101); H05B
6/36 (20060101); B22D 37/00 (20060101); C22C
45/00 (20060101); F27D 11/06 (20060101); B22D
25/06 (20060101); B22D 27/04 (20060101); B22D
27/20 (20060101); B22D 41/01 (20060101); C22C
45/10 (20060101); B22D 18/06 (20060101) |
References Cited
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|
Primary Examiner: Yoon; Kevin E
Assistant Examiner: Yuen; Jacky
Attorney, Agent or Firm: Brownstein Hyatt Farber Schreck,
LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional application of U.S. application
Ser. No. 13/651,654 filed Oct. 15, 2012, now pending, which is
considered part of and is incorporated by reference in its entirety
in the disclosure of this application.
Claims
What is claimed is:
1. A method comprising: placing a material in a horizontally
oriented vessel; operating a first induction coil comprising a
plurality of coil turns at least partially surrounding the vessel
and defining a melt zone at a first RF frequency, thereby forming a
molten material; while operating the first induction coil,
operating a second induction coil at least partially surrounding
the vessel and positioned in line with the first induction coil at
a second RF frequency that is different that the first RF frequency
to contain the material within the melt zone; and forming the
molten material into a bulk metallic glass (BMG) part.
2. The method of claim 1, wherein the second RF frequency is lower
than the first RF frequency.
3. The method of claim 1, further comprising, while operating the
first induction coil, operating an additional induction coil
positioned in line with the first induction coil and at an end of
the vessel opposite the second induction coil at a third RF
frequency that is different than the first RF frequency to contain
the material within the melt zone.
4. The method of claim 3, wherein the third RF frequency is lower
than the first RF frequency.
5. The method of claim 1, wherein: the vessel comprises one or more
temperature regulating channels; and the method further comprises
regulating a temperature of the vessel while operating the first
induction coil by flowing a fluid through the one or more
temperature regulating channels.
6. The method of claim 1, further comprising: stopping operation of
the second induction coil; and ejecting the molten material from
the vessel into a mold to mold the BMG part.
7. The method of claim 6, wherein: the vessel is configured to
receive at least part of a plunger there-through; and the operation
of ejecting the molten material from the vessel into the mold
comprises ejecting the molten material with the plunger.
8. The method of claim 1, further comprising containing the
material within the melt zone without using a physical barrier
along an ejection path of the vessel to contain the material.
9. The method of claim 1, wherein: the material comprises a BMG
feedstock; and the first induction coil is not physically connected
to the second induction coil.
10. The method of claim 1, wherein: the material comprises a BMG
feedstock; and the first induction coil and the second induction
coil are connected as a single induction coil structure comprising
an electrical tap; and the first induction coil and the second
induction coil are independently controlled via the electrical
tap.
11. The method of claim 1, wherein: operating the first induction
coil imparts a first force on the material tending to eject the
material from the melt zone; and operating the second induction
coil imparts a second force on the material in a direction
substantially opposite the first force.
12. A method of operating an apparatus, comprising: operating a
first induction coil at a first RF frequency to form a molten
material in a horizontally oriented vessel; while operating the
first induction coil, operating a second induction coil at a second
RF frequency to contain the molten material within a melt zone
defined by the first induction coil without using a physical
barrier along an ejection path of the vessel, the second RF
frequency being different from the first RF frequency; and ejecting
the molten material from the horizontally oriented vessel and into
a mold.
13. The method of claim 12, wherein the method is performed under
vacuum by applying a vacuum to at least the mold from a vacuum
source.
14. The method of claim 12, wherein the first induction coil at
least partially surrounds the second induction coil.
15. A method comprising: placing a material in a horizontally
oriented vessel; powering a first induction coil comprising a
plurality of coil turns at least partially surrounding the vessel,
thereby forming a molten material; while powering the first
induction coil, powering a second induction coil at least partially
surrounding the vessel to contain the material within an area
surrounded by the first induction coil, the first and the second
induction coil being powered so that a frequency of operation of
the first coil is not synchronized with a frequency of operation of
the second coil; and molding the molten material into a bulk
metallic glass (BMG) part.
16. The method of claim 15, further comprising ejecting the molten
material from the vessel and into a mold cavity to mold the molten
material into the BMG part.
17. The method of claim 15, wherein the second induction coil is
positioned in line with the first induction coil.
18. The method of claim 17, wherein the second induction coil is
spaced apart from the first induction coil.
19. The method of claim 15, wherein: the area surrounded by the
first induction coil defines a melt zone; powering the first
induction coil imparts a first force on the material tending to
eject the material from the melt zone; and powering the second
induction coil imparts a second force on the material in a
direction substantially opposite the first force.
20. The method of claim 15, wherein the second induction coil is at
least partially surrounded by the first induction coil.
Description
FIELD
The present disclosure is generally related to apparatus and
methods for melting materials and for containing the molten
materials within melt zone during melting.
BACKGROUND
Some injection molding machines use an induction coil to melt
material before injecting the material into a mold. However, in
horizontally disposed machines where the material is melted in a
vessel positioned for horizontal ejection, magnetic fluxes from the
induction coil tend to cause the melt to move unpredictably, e.g.,
to flow towards and/or out of the melt zone, which can make it
difficult to control the uniformity and temperature of the
melt.
Current solutions for melting in vessels designed for horizontal
ejection include use of a gate that is in contact with the melt and
physically blocks the melt from flowing (horizontally) out of the
induction coil in the melt zone. Problems arise, however, due to
gate configurations, wherein the gate is a point of contact with
the melt and impurities may be introduced by the gate. In addition,
the gate configuration may reduce the space available for the melt
zone because the gate must be actuated up and down in order to
allow the melt to flow. Further, the melt may undesirably flow
towards and/or out of the horizontal ejection path of the vessel
due to challenge of the timing control as when to raise the gate
during the injection process of the melt. Furthermore, the gate is
potentially a consumable part and needs to be replaced after a
certain number of uses.
It is desirable to contain the melt in the melt zone of
horizontally designed systems at desired high temperatures when it
is heated or melted, but without introducing a gate to physically
block the melt.
SUMMARY
A proposed solution according to embodiments herein for melting
materials (e.g., metals or metal alloys) in a vessel is to contain
the melt or molten material within melt zone.
In accordance with various embodiments, there is provided an
apparatus. The apparatus may include a vessel configured to receive
a material for melting therein; a load induction coil positioned
adjacent to the vessel to melt the material therein; and a
containment induction coil positioned in line with the load
induction coil. The containment induction coil is configured to
contain the melt within the load induction coil.
In accordance with various embodiments, there is provided a melting
method using an apparatus. The apparatus may include a vessel
configured to receive a material for melting therein; a load
induction coil positioned adjacent to the vessel to melt the
material therein; and a containment induction coil positioned in
line with the load induction coil. The material in the vessel can
be heated by operating the load induction coil at a first RF
frequency to form a molten material. While heating, the containment
induction coil can be operated at a second RF frequency to contain
the molten material within the load induction coil.
In accordance with various embodiments, there is provided a melting
method using an apparatus. The apparatus may include a vessel
configured to receive a material for melting therein; a load
induction coil positioned adjacent to the vessel to melt the
material therein; and a containment induction coil positioned in
line with the load induction coil. The material in the vessel can
be heated by operating the load induction coil at a first RF
frequency to form a molten material. While heating, the containment
induction coil can be operated at a second RF frequency to contain
the molten material within the load induction coil. Once the
desired temperature is achieved and maintained for the molten
material, operation of the containment induction coil can be
stopped and the molten material can be ejected from the vessel into
a mold through an ejection path.
Also, in accordance with an embodiment, the material for melting
comprises a BMG feedstock, and a BMG part may be formed.
Further, in an embodiment, the first induction coil and the second
induction coil are part of the same coil, wherein they are
connected to each other electrically but configured in an array
such that a non-uniform magnetic field is produced. In another
embodiment, the first and the second induction coils are part of
the same coil and associated with an electrical tap that allow
independent control of either or both coils, i.e., control of at
least one portion or one side of the single coil, so that the
magnetic field can be changed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A provides a temperature-viscosity diagram of an exemplary
bulk solidifying amorphous alloy.
FIG. 1B provides a schematic of a time-temperature-transformation
(TTT) diagram for an exemplary bulk solidifying amorphous
alloy.
FIGS. 2A to 2D show various exemplary embodiments of the
arrangements of the first induction coil and a second induction,
for melting and containment of a material.
FIG. 3 shows a schematic diagram of an exemplary injection molding
system/apparatus in accordance with various embodiments of the
present teachings.
FIG. 4 depicts an injection molding system configured having an
induction coil.
FIG. 5 depicts another exemplary injection molding system/apparatus
in accordance with various embodiments of the present
teachings.
FIG. 6 depicts a method for melting/molding a material in
accordance with various embodiments of the present teachings.
DETAILED DESCRIPTION
All publications, patents, and patent applications cited in this
Specification are hereby incorporated by reference in their
entirety.
The articles "a" and "an" are used herein to refer to one or to
more than one (i.e., to at least one) of the grammatical object of
the article. By way of example, "a polymer resin" means one polymer
resin or more than one polymer resin. Any ranges cited herein are
inclusive. The terms "substantially" and "about" used throughout
this Specification are used to describe and account for small
fluctuations. For example, they can refer to less than or equal to
.+-.5%, such as less than or equal to .+-.2%, such as less than or
equal to .+-.1%, such as less than or equal to .+-.0.5%, such as
less than or equal to .+-.0.2%, such as less than or equal to
.+-.0.1%, such as less than or equal to .+-.0.05%.
Bulk-solidifying amorphous alloys, or bulk metallic glasses
("BMG"), are a recently developed class of metallic materials.
These alloys may be solidified and cooled at relatively slow rates,
and they retain the amorphous, non-crystalline (i.e., glassy) state
at room temperature. Amorphous alloys have many superior properties
than their crystalline counterparts. However, if the cooling rate
is not sufficiently high, crystals may form inside the alloy during
cooling, so that the benefits of the amorphous state can be lost.
For example, one challenge with the fabrication of bulk amorphous
alloy parts is partial crystallization of the parts due to either
slow cooling or impurities in the raw alloy material. As a high
degree of amorphicity (and, conversely, a low degree of
crystallinity) is desirable in BMG parts, there is a need to
develop methods for casting BMG parts having controlled amount of
amorphicity.
FIG. 1A (obtained from U.S. Pat. No. 7,575,040) shows a
viscosity-temperature graph of an exemplary bulk solidifying
amorphous alloy, from the VIT-001 series of Zr--Ti--Ni--Cu--Be
family manufactured by Liquidmetal Technology. It should be noted
that there is no clear liquid/solid transformation for a bulk
solidifying amorphous metal during the formation of an amorphous
solid. The molten alloy becomes more and more viscous with
increasing undercooling until it approaches solid form around the
glass transition temperature. Accordingly, the temperature of
solidification front for bulk solidifying amorphous alloys can be
around glass transition temperature, where the alloy will
practically act as a solid for the purposes of pulling out the
quenched amorphous sheet product.
FIG. 1B (obtained from U.S. Pat. No. 7,575,040) shows the
time-temperature-transformation (TTT) cooling curve of an exemplary
bulk solidifying amorphous alloy, or TTT diagram. Bulk-solidifying
amorphous metals do not experience a liquid/solid crystallization
transformation upon cooling, as with conventional metals. Instead,
the highly fluid, non crystalline form of the metal found at high
temperatures (near a "melting temperature" Tm) becomes more viscous
as the temperature is reduced (near to the glass transition
temperature Tg), eventually taking on the outward physical
properties of a conventional solid.
Even though there is no liquid/crystallization transformation for a
bulk solidifying amorphous metal, a "melting temperature" Tm may be
defined as the thermodynamic liquidus temperature of the
corresponding crystalline phase. Under this regime, the viscosity
of bulk-solidifying amorphous alloys at the melting temperature
could lie in the range of about 0.1 poise to about 10,000 poise,
and even sometimes under 0.01 poise. A lower viscosity at the
"melting temperature" would provide faster and complete filling of
intricate portions of the shell/mold with a bulk solidifying
amorphous metal for forming the BMG parts. Furthermore, the cooling
rate of the molten metal to form a BMG part has to such that the
time-temperature profile during cooling does not traverse through
the nose-shaped region bounding the crystallized region in the TTT
diagram of FIG. 1B. In FIG. 1B, Tnose is the critical
crystallization temperature Tx where crystallization is most rapid
and occurs in the shortest time scale.
The supercooled liquid region, the temperature region between Tg
and Tx is a manifestation of the extraordinary stability against
crystallization of bulk solidification alloys. In this temperature
region the bulk solidifying alloy can exist as a high viscous
liquid. The viscosity of the bulk solidifying alloy in the
supercooled liquid region can vary between 10.sup.12 Pa s at the
glass transition temperature down to 10.sup.5 Pa s at the
crystallization temperature, the high temperature limit of the
supercooled liquid region. Liquids with such viscosities can
undergo substantial plastic strain under an applied pressure. The
embodiments herein make use of the large plastic formability in the
supercooled liquid region as a forming and separating method.
One needs to clarify something about Tx. Technically, the
nose-shaped curve shown in the TTT diagram describes Tx as a
function of temperature and time. Thus, regardless of the
trajectory that one takes while heating or cooling a metal alloy,
when one hits the TTT curve, one has reached Tx. In FIG. 1B, Tx is
shown as a dashed line as Tx can vary from close to Tm to close to
Tg.
The schematic TTT diagram of FIG. 1B shows processing methods of
die casting from at or above Tm to below Tg without the
time-temperature trajectory (shown as (1) as an example trajectory)
hitting the TTT curve. During die casting, the forming takes place
substantially simultaneously with fast cooling to avoid the
trajectory hitting the TTT curve. The processing methods for
superplastic forming (SPF) from at or below Tg to below Tm without
the time-temperature trajectory (shown as (2), (3) and (4) as
example trajectories) hitting the TTT curve. In SPF, the amorphous
BMG is reheated into the supercooled liquid region where the
available processing window could be much larger than die casting,
resulting in better controllability of the process. The SPF process
does not require fast cooling to avoid crystallization during
cooling. Also, as shown by example trajectories (2), (3) and (4),
the SPF can be carried out with the highest temperature during SPF
being above Tnose or below Tnose, up to about Tm. If one heats up a
piece of amorphous alloy but manages to avoid hitting the TTT
curve, you have heated "between Tg and Tm", but one would have not
reached Tx.
Typical differential scanning calorimeter (DSC) heating curves of
bulk-solidifying amorphous alloys taken at a heating rate of 20
C/min describe, for the most part, a particular trajectory across
the TTT data where one would likely see a Tg at a certain
temperature, a Tx when the DSC heating ramp crosses the TTT
crystallization onset, and eventually melting peaks when the same
trajectory crosses the temperature range for melting. If one heats
a bulk-solidifying amorphous alloy at a rapid heating rate as shown
by the ramp up portion of trajectories (2), (3) and (4) in FIG. 1B,
then one could avoid the TTT curve entirely, and the DSC data would
show a glass transition but no Tx upon heating. Another way to
think about it is trajectories (2), (3) and (4) can fall anywhere
in temperature between the nose of the TTT curve (and even above
it) and the Tg line, as long as it does not hit the crystallization
curve. That just means that the horizontal plateau in trajectories
might get much shorter as one increases the processing
temperature.
Phase
The term "phase" herein can refer to one that can be found in a
thermodynamic phase diagram. A phase is a region of space (e.g., a
thermodynamic system) throughout which all physical properties of a
material are essentially uniform. Examples of physical properties
include density, index of refraction, chemical composition and
lattice periodicity. A simple description of a phase is a region of
material that is chemically uniform, physically distinct, and/or
mechanically separable. For example, in a system consisting of ice
and water in a glass jar, the ice cubes are one phase, the water is
a second phase, and the humid air over the water is a third phase.
The glass of the jar is another separate phase. A phase can refer
to a solid solution, which can be a binary, tertiary, quaternary,
or more, solution, or a compound, such as an intermetallic
compound. As another example, an amorphous phase is distinct from a
crystalline phase.
Metal, Transition Metal, and Non-Metal
The term "metal" refers to an electropositive chemical element. The
term "element" in this Specification refers generally to an element
that can be found in a Periodic Table. Physically, a metal atom in
the ground state contains a partially filled band with an empty
state close to an occupied state. The term "transition metal" is
any of the metallic elements within Groups 3 to 12 in the Periodic
Table that have an incomplete inner electron shell and that serve
as transitional links between the most and the least
electropositive in a series of elements. Transition metals are
characterized by multiple valences, colored compounds, and the
ability to form stable complex ions. The term "nonmetal" refers to
a chemical element that does not have the capacity to lose
electrons and form a positive ion.
Depending on the application, any suitable nonmetal elements, or
their combinations, can be used. The alloy (or "alloy composition")
can include multiple nonmetal elements, such as at least two, at
least three, at least four, or more, nonmetal elements. A nonmetal
element can be any element that is found in Groups 13-17 in the
Periodic Table. For example, a nonmetal element can be any one of
F, Cl, Br, I, At, O, S, Se, Te, Po, N, P, As, Sb, Bi, C, Si, Ge,
Sn, Pb, and B. Occasionally, a nonmetal element can also refer to
certain metalloids (e.g., B, Si, Ge, As, Sb, Te, and Po) in Groups
13-17. In one embodiment, the nonmetal elements can include B, Si,
C, P, or combinations thereof. Accordingly, for example, the alloy
can include a boride, a carbide, or both.
A transition metal element can be any of scandium, titanium,
vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc,
yttrium, zirconium, niobium, molybdenum, technetium, ruthenium,
rhodium, palladium, silver, cadmium, hafnium, tantalum, tungsten,
rhenium, osmium, iridium, platinum, gold, mercury, rutherfordium,
dubnium, seaborgium, bohrium, hassium, meitnerium, ununnilium,
unununium, and ununbium. In one embodiment, a BMG containing a
transition metal element can have at least one of Sc, Y, La, Ac,
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh,
Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg. Depending on the
application, any suitable transitional metal elements, or their
combinations, can be used. The alloy composition can include
multiple transitional metal elements, such as at least two, at
least three, at least four, or more, transitional metal
elements.
The presently described alloy or alloy "sample" or "specimen" alloy
can have any shape or size. For example, the alloy can have a shape
of a particulate, which can have a shape such as spherical,
ellipsoid, wire-like, rod-like, sheet-like, flake-like, or an
irregular shape. The particulate can have any size. For example, it
can have an average diameter of between about 1 micron and about
100 microns, such as between about 5 microns and about 80 microns,
such as between about 10 microns and about 60 microns, such as
between about 15 microns and about 50 microns, such as between
about 15 microns and about 45 microns, such as between about 20
microns and about 40 microns, such as between about 25 microns and
about 35 microns. For example, in one embodiment, the average
diameter of the particulate is between about 25 microns and about
44 microns. In some embodiments, smaller particulates, such as
those in the nanometer range, or larger particulates, such as those
bigger than 100 microns, can be used.
The alloy sample or specimen can also be of a much larger
dimension. For example, it can be a bulk structural component, such
as an ingot, housing/casing of an electronic device or even a
portion of a structural component that has dimensions in the
millimeter, centimeter, or meter range.
Solid Solution
The term "solid solution" refers to a solid form of a solution. The
term "solution" refers to a mixture of two or more substances,
which may be solids, liquids, gases, or a combination of these. The
mixture can be homogeneous or heterogeneous. The term "mixture" is
a composition of two or more substances that are combined with each
other and are generally capable of being separated. Generally, the
two or more substances are not chemically combined with each
other.
Alloy
In some embodiments, the alloy composition described herein can be
fully alloyed. In one embodiment, an "alloy" refers to a
homogeneous mixture or solid solution of two or more metals, the
atoms of one replacing or occupying interstitial positions between
the atoms of the other; for example, brass is an alloy of zinc and
copper. An alloy, in contrast to a composite, can refer to a
partial or complete solid solution of one or more elements in a
metal matrix, such as one or more compounds in a metallic matrix.
The term alloy herein can refer to both a complete solid solution
alloy that can give single solid phase microstructure and a partial
solution that can give two or more phases. An alloy composition
described herein can refer to one comprising an alloy or one
comprising an alloy-containing composite.
Thus, a fully alloyed alloy can have a homogenous distribution of
the constituents, be it a solid solution phase, a compound phase,
or both. The term "fully alloyed" used herein can account for minor
variations within the error tolerance. For example, it can refer to
at least 90% alloyed, such as at least 95% alloyed, such as at
least 99% alloyed, such as at least 99.5% alloyed, such as at least
99.9% alloyed. The percentage herein can refer to either volume
percent or weight percentage, depending on the context. These
percentages can be balanced by impurities, which can be in terms of
composition or phases that are not a part of the alloy.
Amorphous or Non-Crystalline Solid
An "amorphous" or "non-crystalline solid" is a solid that lacks
lattice periodicity, which is characteristic of a crystal. As used
herein, an "amorphous solid" includes "glass" which is an amorphous
solid that softens and transforms into a liquid-like state upon
heating through the glass transition. Generally, amorphous
materials lack the long-range order characteristic of a crystal,
though they can possess some short-range order at the atomic length
scale due to the nature of chemical bonding. The distinction
between amorphous solids and crystalline solids can be made based
on lattice periodicity as determined by structural characterization
techniques such as x-ray diffraction and transmission electron
microscopy.
The terms "order" and "disorder" designate the presence or absence
of some symmetry or correlation in a many-particle system. The
terms "long-range order" and "short-range order" distinguish order
in materials based on length scales.
The strictest form of order in a solid is lattice periodicity: a
certain pattern (the arrangement of atoms in a unit cell) is
repeated again and again to form a translationally invariant tiling
of space. This is the defining property of a crystal. Possible
symmetries have been classified in 14 Bravais lattices and 230
space groups.
Lattice periodicity implies long-range order. If only one unit cell
is known, then by virtue of the translational symmetry it is
possible to accurately predict all atomic positions at arbitrary
distances. The converse is generally true, except, for example, in
quasi-crystals that have perfectly deterministic tilings but do not
possess lattice periodicity.
Long-range order characterizes physical systems in which remote
portions of the same sample exhibit correlated behavior. This can
be expressed as a correlation function, namely the spin-spin
correlation function: G(x,x')=s(x),s(x').
In the above function, s is the spin quantum number and x is the
distance function within the particular system. This function is
equal to unity when x=x' and decreases as the distance |x-x'|
increases. Typically, it decays exponentially to zero at large
distances, and the system is considered to be disordered. If,
however, the correlation function decays to a constant value at
large |x-x'|, then the system can be said to possess long-range
order. If it decays to zero as a power of the distance, then it can
be called quasi-long-range order. Note that what constitutes a
large value of |x-x'| is relative.
A system can be said to present quenched disorder when some
parameters defining its behavior are random variables that do not
evolve with time (i.e., they are quenched or frozen)--e.g., spin
glasses. It is opposite to annealed disorder, where the random
variables are allowed to evolve themselves. Embodiments herein
include systems comprising quenched disorder.
The alloy described herein can be crystalline, partially
crystalline, amorphous, or substantially amorphous. For example,
the alloy sample/specimen can include at least some crystallinity,
with grains/crystals having sizes in the nanometer and/or
micrometer ranges. Alternatively, the alloy can be substantially
amorphous, such as fully amorphous. In one embodiment, the alloy
composition is at least substantially not amorphous, such as being
substantially crystalline, such as being entirely crystalline.
In one embodiment, the presence of a crystal or a plurality of
crystals in an otherwise amorphous alloy can be construed as a
"crystalline phase" therein. The degree of crystallinity (or
"crystallinity" for short in some embodiments) of an alloy can
refer to the amount of the crystalline phase present in the alloy.
The degree can refer to, for example, a fraction of crystals
present in the alloy. The fraction can refer to volume fraction or
weight fraction, depending on the context. A measure of how
"amorphous" an amorphous alloy is can be amorphicity. Amorphicity
can be measured in terms of a degree of crystallinity. For example,
in one embodiment, an alloy having a low degree of crystallinity
can be said to have a high degree of amorphicity. In one
embodiment, for example, an alloy having 60 vol % crystalline phase
can have a 40 vol % amorphous phase.
Amorphous Alloy or Amorphous Metal
An "amorphous alloy" is an alloy having an amorphous content of
more than 50% by volume, preferably more than 90% by volume of
amorphous content, more preferably more than 95% by volume of
amorphous content, and most preferably more than 99% to almost 100%
by volume of amorphous content. Note that, as described above, an
alloy high in amorphicity is equivalently low in degree of
crystallinity. An "amorphous metal" is an amorphous metal material
with a disordered atomic-scale structure. In contrast to most
metals, which are crystalline and therefore have a highly ordered
arrangement of atoms, amorphous alloys are non-crystalline.
Materials in which such a disordered structure is produced directly
from the liquid state during cooling are sometimes referred to as
"glasses." Accordingly, amorphous metals are commonly referred to
as "metallic glasses" or "glassy metals." In one embodiment, a bulk
metallic glass ("BMG") can refer to an alloy, of which the
microstructure is at least partially amorphous. However, there are
several ways besides extremely rapid cooling to produce amorphous
metals, including physical vapor deposition, solid-state reaction,
ion irradiation, melt spinning, and mechanical alloying. Amorphous
alloys can be a single class of materials, regardless of how they
are prepared.
Amorphous metals can be produced through a variety of quick-cooling
methods. For instance, amorphous metals can be produced by
sputtering molten metal onto a spinning metal disk. The rapid
cooling, on the order of millions of degrees a second, can be too
fast for crystals to form, and the material is thus "locked in" a
glassy state. Also, amorphous metals/alloys can be produced with
critical cooling rates low enough to allow formation of amorphous
structures in thick layers--e.g., bulk metallic glasses.
The terms "bulk metallic glass" ("BMG"), bulk amorphous alloy
("BAA"), and bulk solidifying amorphous alloy are used
interchangeably herein. They refer to amorphous alloys having the
smallest dimension at least in the millimeter range. For example,
the dimension can be at least about 0.5 mm, such as at least about
1 mm, such as at least about 2 mm, such as at least about 4 mm,
such as at least about 5 mm, such as at least about 6 mm, such as
at least about 8 mm, such as at least about 10 mm, such as at least
about 12 mm. Depending on the geometry, the dimension can refer to
the diameter, radius, thickness, width, length, etc. A BMG can also
be a metallic glass having at least one dimension in the centimeter
range, such as at least about 1.0 cm, such as at least about 2.0
cm, such as at least about 5.0 cm, such as at least about 10.0 cm.
In some embodiments, a BMG can have at least one dimension at least
in the meter range. A BMG can take any of the shapes or forms
described above, as related to a metallic glass. Accordingly, a BMG
described herein in some embodiments can be different from a thin
film made by a conventional deposition technique in one important
aspect--the former can be of a much larger dimension than the
latter.
Amorphous metals can be an alloy rather than a pure metal. The
alloys may contain atoms of significantly different sizes, leading
to low free volume (and therefore having viscosity up to orders of
magnitude higher than other metals and alloys) in a molten state.
The viscosity prevents the atoms from moving enough to form an
ordered lattice. The material structure may result in low shrinkage
during cooling and resistance to plastic deformation. The absence
of grain boundaries, the weak spots of crystalline materials in
some cases, may, for example, lead to better resistance to wear and
corrosion. In one embodiment, amorphous metals, while technically
glasses, may also be much tougher and less brittle than oxide
glasses and ceramics.
Thermal conductivity of amorphous materials may be lower than that
of their crystalline counterparts. To achieve formation of an
amorphous structure even during slower cooling, the alloy may be
made of three or more components, leading to complex crystal units
with higher potential energy and lower probability of formation.
The formation of amorphous alloy can depend on several factors: the
composition of the components of the alloy; the atomic radius of
the components (preferably with a significant difference of over
12% to achieve high packing density and low free volume); and the
negative heat of mixing the combination of components, inhibiting
crystal nucleation and prolonging the time the molten metal stays
in a supercooled state. However, as the formation of an amorphous
alloy is based on many different variables, it can be difficult to
make a prior determination of whether an alloy composition would
form an amorphous alloy.
Amorphous alloys, for example, of boron, silicon, phosphorus, and
other glass formers with magnetic metals (iron, cobalt, nickel) may
be magnetic, with low coercivity and high electrical resistance.
The high resistance leads to low losses by eddy currents when
subjected to alternating magnetic fields, a property useful, for
example, as transformer magnetic cores.
Amorphous alloys may have a variety of potentially useful
properties. In particular, they tend to be stronger than
crystalline alloys of similar chemical composition, and they can
sustain larger reversible ("elastic") deformations than crystalline
alloys. Amorphous metals derive their strength directly from their
non-crystalline structure, which can have none of the defects (such
as dislocations) that limit the strength of crystalline alloys. For
example, one modern amorphous metal, known as Vitreloy.TM., has a
tensile strength that is almost twice that of high-grade titanium.
In some embodiments, metallic glasses at room temperature are not
ductile and tend to fail suddenly when loaded in tension, which
limits the material applicability in reliability-critical
applications, as the impending failure is not evident. Therefore,
to overcome this challenge, metal matrix composite materials having
a metallic glass matrix containing dendritic particles or fibers of
a ductile crystalline metal can be used. Alternatively, a BMG low
in element(s) that tend to cause embitterment (e.g., Ni) can be
used. For example, a Ni-free BMG can be used to improve the
ductility of the BMG.
Another useful property of bulk amorphous alloys is that they can
be true glasses; in other words, they can soften and flow upon
heating. This can allow for easy processing, such as by injection
molding, in much the same way as polymers. As a result, amorphous
alloys can be used for making sports equipment, medical devices,
electronic components and equipment, and thin films. Thin films of
amorphous metals can be deposited as protective coatings via a high
velocity oxygen fuel technique.
A material can have an amorphous phase, a crystalline phase, or
both. The amorphous and crystalline phases can have the same
chemical composition and differ only in the microstructure--i.e.,
one amorphous and the other crystalline. Microstructure in one
embodiment refers to the structure of a material as revealed by a
microscope at 25.times. magnification or higher. Alternatively, the
two phases can have different chemical compositions and
microstructures. For example, a composition can be partially
amorphous, substantially amorphous, or completely amorphous.
As described above, the degree of amorphicity (and conversely the
degree of crystallinity) can be measured by fraction of crystals
present in the alloy. The degree can refer to volume fraction of
weight fraction of the crystalline phase present in the alloy. A
partially amorphous composition can refer to a composition of at
least about 5 vol % of which is of an amorphous phase, such as at
least about 10 vol %, such as at least about 20 vol %, such as at
least about 40 vol %, such as at least about 60 vol %, such as at
least about 80 vol %, such as at least about 90 vol %. The terms
"substantially" and "about" have been defined elsewhere in this
application. Accordingly, a composition that is at least
substantially amorphous can refer to one of which at least about 90
vol % is amorphous, such as at least about 95 vol %, such as at
least about 98 vol %, such as at least about 99 vol %, such as at
least about 99.5 vol %, such as at least about 99.8 vol %, such as
at least about 99.9 vol %. In one embodiment, a substantially
amorphous composition can have some incidental, insignificant
amount of crystalline phase present therein.
In one embodiment, an amorphous alloy composition can be
homogeneous with respect to the amorphous phase. A substance that
is uniform in composition is homogeneous. This is in contrast to a
substance that is heterogeneous. The term "composition" refers to
the chemical composition and/or microstructure in the substance. A
substance is homogeneous when a volume of the substance is divided
in half and both halves have substantially the same composition.
For example, a particulate suspension is homogeneous when a volume
of the particulate suspension is divided in half and both halves
have substantially the same volume of particles. However, it might
be possible to see the individual particles under a microscope.
Another example of a homogeneous substance is air where different
ingredients therein are equally suspended, though the particles,
gases and liquids in air can be analyzed separately or separated
from air.
A composition that is homogeneous with respect to an amorphous
alloy can refer to one having an amorphous phase substantially
uniformly distributed throughout its microstructure. In other
words, the composition macroscopically includes a substantially
uniformly distributed amorphous alloy throughout the composition.
In an alternative embodiment, the composition can be of a
composite, having an amorphous phase having therein a non-amorphous
phase. The non-amorphous phase can be a crystal or a plurality of
crystals. The crystals can be in the form of particulates of any
shape, such as spherical, ellipsoid, wire-like, rod-like,
sheet-like, flake-like, or an irregular shape. In one embodiment,
it can have a dendritic form. For example, an at least partially
amorphous composite composition can have a crystalline phase in the
shape of dendrites dispersed in an amorphous phase matrix; the
dispersion can be uniform or non-uniform, and the amorphous phase
and the crystalline phase can have the same or a different chemical
composition. In one embodiment, they have substantially the same
chemical composition. In another embodiment, the crystalline phase
can be more ductile than the BMG phase.
The methods described herein can be applicable to any type of
amorphous alloy. Similarly, the amorphous alloy described herein as
a constituent of a composition or article can be of any type. The
amorphous alloy can include the element Zr, Hf, Ti, Cu, Ni, Pt, Pd,
Fe, Mg, Au, La, Ag, Al, Mo, Nb, Be, or combinations thereof.
Namely, the alloy can include any combination of these elements in
its chemical formula or chemical composition. The elements can be
present at different weight or volume percentages. For example, an
iron "based" alloy can refer to an alloy having a non-insignificant
weight percentage of iron present therein, the weight percent can
be, for example, at least about 20 wt %, such as at least about 40
wt %, such as at least about 50 wt %, such as at least about 60 wt
%, such as at least about 80 wt %. Alternatively, in one
embodiment, the above-described percentages can be volume
percentages, instead of weight percentages. Accordingly, an
amorphous alloy can be zirconium-based, titanium-based,
platinum-based, palladium-based, gold-based, silver-based,
copper-based, iron-based, nickel-based, aluminum-based,
molybdenum-based, and the like. The alloy can also be free of any
of the aforementioned elements to suit a particular purpose. For
example, in some embodiments, the alloy, or the composition
including the alloy, can be substantially free of nickel, aluminum,
titanium, beryllium, or combinations thereof. In one embodiment,
the alloy or the composite is completely free of nickel, aluminum,
titanium, beryllium, or combinations thereof.
For example, the amorphous alloy can have the formula (Zr,
Ti).sub.a(Ni, Cu, Fe).sub.b(Be, Al, Si, B).sub.c, wherein a, b, and
c each represents a weight or atomic percentage. In one embodiment,
a is in the range of from 30 to 75, b is in the range of from 5 to
60, and c is in the range of from 0 to 50 in atomic percentages.
Alternatively, the amorphous alloy can have the formula (Zr,
Ti).sub.a(Ni, Cu).sub.b(Be).sub.c, wherein a, b, and c each
represents a weight or atomic percentage. In one embodiment, a is
in the range of from 40 to 75, b is in the range of from 5 to 50,
and c is in the range of from 5 to 50 in atomic percentages. The
alloy can also have the formula (Zr, Ti).sub.a(Ni,
Cu).sub.b(Be).sub.c, wherein a, b, and c each represents a weight
or atomic percentage. In one embodiment, a is in the range of from
45 to 65, b is in the range of from 7.5 to 35, and c is in the
range of from 10 to 37.5 in atomic percentages. Alternatively, the
alloy can have the formula (Zr).sub.a(Nb, Ti).sub.b(Ni,
Cu).sub.c(Al).sub.d, wherein a, b, c, and d each represents a
weight or atomic percentage. In one embodiment, a is in the range
of from 45 to 65, b is in the range of from 0 to 10, c is in the
range of from 20 to 40 and d is in the range of from 7.5 to 15 in
atomic percentages. One exemplary embodiment of the aforedescribed
alloy system is a Zr--Ti--Ni--Cu--Be based amorphous alloy under
the trade name Vitreloy.TM., such as Vitreloy-1 and Vitreloy-101,
as fabricated by Liquidmetal Technologies, CA, USA. Some examples
of amorphous alloys of the different systems are provided in Table
1 and Table 2.
TABLE-US-00001 TABLE 1 Exemplary amorphous alloy compositions Alloy
Atm % Atm % Atm % Atm % Atm % Atm % Atm % Atm % 1 Fe Mo Ni Cr P C B
68.00% 5.00% 5.00% 2.00% 12.50% 5.00% 2.50% 2 Fe Mo Ni Cr P C B Si
68.00% 5.00% 5.00% 2.00% 11.00% 5.00% 2.50% 1.50% 3 Pd Cu Co P
44.48% 32.35% 4.05% 19.11% 4 Pd Ag Si P 77.50% 6.00% 9.00% 7.50% 5
Pd Ag Si P Ge 79.00% 3.50% 9.50% 6.00% 2.00% 6 Pt Cu Ag P B Si
74.70% 1.50% 0.30% 18.0% 4.00% 1.50%
TABLE-US-00002 TABLE 2 Additional Exemplary amorphous alloy
compositions (atomic %) Alloy Atm % Atm % Atm % Atm % Atm % Atm % 1
Zr Ti Cu Ni Be 41.20% 13.80% 12.50% 10.00% 22.50% 2 Zr Ti Cu Ni Be
44.00% 11.00% 10.00% 10.00% 25.00% 3 Zr Ti Cu Ni Nb Be 56.25%
11.25% 6.88% 5.63% 7.50% 12.50% 4 Zr Ti Cu Ni Al Be 64.75% 5.60%
14.90% 11.15% 2.60% 1.00% 5 Zr Ti Cu Ni Al 52.50% 5.00% 17.90%
14.60% 10.00% 6 Zr Nb Cu Ni Al 57.00% 5.00% 15.40% 12.60% 10.00% 7
Zr Cu Ni Al 50.75% 36.23% 4.03% 9.00% 8 Zr Ti Cu Ni Be 46.75% 8.25%
7.50% 10.00% 27.50% 9 Zr Ti Ni Be 21.67% 43.33% 7.50% 27.50% 10 Zr
Ti Cu Be 35.00% 30.00% 7.50% 27.50% 11 Zr Ti Co Be 35.00% 30.00%
6.00% 29.00% 12 Zr Ti Fe Be 35.00% 30.00% 2.00% 33.00% 13 Au Ag Pd
Cu Si 49.00% 5.50% 2.30% 26.90% 16.30% 14 Au Ag Pd Cu Si 50.90%
3.00% 2.30% 27.80% 16.00% 15 Pt Cu Ni P 57.50% 14.70% 5.30% 22.50%
16 Zr Ti Nb Cu Be 36.60% 31.40% 7.00% 5.90% 19.10% 17 Zr Ti Nb Cu
Be 38.30% 32.90% 7.30% 6.20% 15.30% 18 Zr Ti Nb Cu Be 39.60% 33.90%
7.60% 6.40% 12.50% 19 Cu Ti Zr Ni 47.00% 34.00% 11.00% 8.00% 20 Zr
Co Al 55.00% 25.00% 20.00%
Other exemplary ferrous metal-based alloys include compositions
such as those disclosed in U.S. Patent Application Publication Nos.
2007/0079907 and 2008/0305387. These compositions include the
Fe(Mn, Co, Ni, Cu) (C, Si, B, P, Al) system, wherein the Fe content
is from 60 to 75 atomic percentage, the total of (Mn, Co, Ni, Cu)
is in the range of from 5 to 25 atomic percentage, and the total of
(C, Si, B, P, Al) is in the range of from 8 to 20 atomic
percentage, as well as the exemplary composition
Fe48Cr15Mo14Y2C15B6. They also include the alloy systems described
by Fe--Cr--Mo--(Y,Ln)-C--B, Co--Cr--Mo-Ln-C--B,
Fe--Mn--Cr--Mo--(Y,Ln)-C--B, (Fe, Cr, Co)--(Mo,Mn)--(C,B)--Y,
Fe--(Co,Ni)--(Zr,Nb,Ta)--(Mo,W)--B, Fe--(Al,Ga)--(P,C,B,Si,Ge),
Fe--(Co, Cr,Mo,Ga,Sb)--P--B--C, (Fe, Co)--B--Si--Nb alloys, and
Fe--(Cr--Mo)--(C,B)--Tm, where Ln denotes a lanthanide element and
Tm denotes a transition metal element. Furthermore, the amorphous
alloy can also be one of the exemplary compositions
Fe80P12.5C5B2.5, Fe80P11C5B2.5Si1.5, Fe74.5Mo5.5P12.5C5B2.5,
Fe74.5Mo5.5P11C5B2.5Si1.5, Fe70Mo5Ni5P12.5C5B2.5,
Fe70Mo5Ni5P11C5B2.5Si1.5, Fe68Mo5Ni5Cr2P12.5C5B2.5, and
Fe68Mo5Ni5Cr2P11C5B2.5Si1.5, described in U.S. Patent Application
Publication No. 2010/0300148.
The amorphous alloys can also be ferrous alloys, such as (Fe, Ni,
Co) based alloys. Examples of such compositions are disclosed in
U.S. Pat. Nos. 6,325,868; 5,288,344; 5,368,659; 5,618,359; and
5,735,975, Inoue et al., Appl. Phys. Lett., Volume 71, p 464
(1997), Shen et al., Mater. Trans., JIM, Volume 42, p 2136 (2001),
and Japanese Patent Application No. 200126277 (Pub. No. 2001303218
A). One exemplary composition is
Fe.sub.72Al.sub.5Ga.sub.2P.sub.11C.sub.6B.sub.4. Another example is
Fe.sub.72Al.sub.7Zr.sub.10Mo.sub.5W.sub.2B.sub.15. Another
iron-based alloy system that can be used in the coating herein is
disclosed in U.S. Patent Application Publication No. 2010/0084052,
wherein the amorphous metal contains, for example, manganese (1 to
3 atomic %), yttrium (0.1 to 10 atomic %), and silicon (0.3 to 3.1
atomic %) in the range of composition given in parentheses; and
that contains the following elements in the specified range of
composition given in parentheses: chromium (15 to 20 atomic %),
molybdenum (2 to 15 atomic %), tungsten (1 to 3 atomic %), boron (5
to 16 atomic %), carbon (3 to 16 atomic %), and the balance
iron.
The amorphous alloy can also be one of the Pt- or Pd-based alloys
described by U.S. Patent Application Publication Nos. 2008/0135136,
2009/0162629, and 2010/0230012. Exemplary compositions include
Pd44.48Cu32.35Cu4.05P19.11, Pd77.5Ag6Si9P7.5, and
Pt74.7Cul.5Ag0.3P18B4Si1.5.
The aforedescribed amorphous alloy systems can further include
additional elements, such as additional transition metal elements,
including Nb, Cr, V, and Co. The additional elements can be present
at less than or equal to about 30 wt %, such as less than or equal
to about 20 wt %, such as less than or equal to about 10 wt %, such
as less than or equal to about 5 wt %. In one embodiment, the
additional, optional element is at least one of cobalt, manganese,
zirconium, tantalum, niobium, tungsten, yttrium, titanium, vanadium
and hafnium to form carbides and further improve wear and corrosion
resistance. Further optional elements may include phosphorous,
germanium and arsenic, totaling up to about 2%, and preferably less
than 1%, to reduce melting point. Otherwise incidental impurities
should be less than about 2% and preferably 0.5%.
In some embodiments, a composition having an amorphous alloy can
include a small amount of impurities. The impurity elements can be
intentionally added to modify the properties of the composition,
such as improving the mechanical properties (e.g., hardness,
strength, fracture mechanism, etc.) and/or improving the corrosion
resistance. Alternatively, the impurities can be present as
inevitable, incidental impurities, such as those obtained as a
byproduct of processing and manufacturing. The impurities can be
less than or equal to about 10 wt %, such as about 5 wt %, such as
about 2 wt %, such as about 1 wt %, such as about 0.5 wt %, such as
about 0.1 wt %. In some embodiments, these percentages can be
volume percentages instead of weight percentages. In one
embodiment, the alloy sample/composition consists essentially of
the amorphous alloy (with only a small incidental amount of
impurities). In another embodiment, the composition includes the
amorphous alloy (with no observable trace of impurities).
In one embodiment, the final parts exceeded the critical casting
thickness of the bulk solidifying amorphous alloys.
In embodiments herein, the existence of a supercooled liquid region
in which the bulk-solidifying amorphous alloy can exist as a high
viscous liquid allows for superplastic forming. Large plastic
deformations can be obtained. The ability to undergo large plastic
deformation in the supercooled liquid region is used for the
forming and/or cutting process. As oppose to solids, the liquid
bulk solidifying alloy deforms locally which drastically lowers the
required energy for cutting and forming. The ease of cutting and
forming depends on the temperature of the alloy, the mold, and the
cutting tool. As higher is the temperature, the lower is the
viscosity, and consequently easier is the cutting and forming.
Embodiments herein can utilize a thermoplastic-forming process with
amorphous alloys carried out between Tg and Tx, for example.
Herein, Tx and Tg are determined from standard DSC measurements at
typical heating rates (e.g. 20.degree. C./min) as the onset of
crystallization temperature and the onset of glass transition
temperature.
The amorphous alloy components can have the critical casting
thickness and the final part can have thickness that is thicker
than the critical casting thickness. Moreover, the time and
temperature of the heating and shaping operation is selected such
that the elastic strain limit of the amorphous alloy could be
substantially preserved to be not less than 1.0%, and preferably
not being less than 1.5%. In the context of the embodiments herein,
temperatures around glass transition means the forming temperatures
can be below glass transition, at or around glass transition, and
above glass transition temperature, but preferably at temperatures
below the crystallization temperature T.sub.x. The cooling step is
carried out at rates similar to the heating rates at the heating
step, and preferably at rates greater than the heating rates at the
heating step. The cooling step is also achieved preferably while
the forming and shaping loads are still maintained.
Electronic Devices
The embodiments herein can be valuable in the fabrication of
electronic devices using a BMG. An electronic device herein can
refer to any electronic device known in the art. For example, it
can be a telephone, such as a cell phone, and a land-line phone, or
any communication device, such as a smart phone, including, for
example an iPhone.TM., and an electronic email sending/receiving
device. It can be a part of a display, such as a digital display, a
TV monitor, an electronic-book reader, a portable web-browser
(e.g., iPad.TM.), and a computer monitor. It can also be an
entertainment device, including a portable DVD player, conventional
DVD player, Blu-Ray disk player, video game console, music player,
such as a portable music player (e.g., iPod.TM.), etc. It can also
be a part of a device that provides control, such as controlling
the streaming of images, videos, sounds (e.g., Apple TV.TM.), or it
can be a remote control for an electronic device. It can be a part
of a computer or its accessories, such as the hard drive tower
housing or casing, laptop housing, laptop keyboard, laptop track
pad, desktop keyboard, mouse, and speaker. The article can also be
applied to a device such as a watch or a clock.
A proposed solution according to embodiments herein for melting
materials (e.g., metals or metal alloys) in a vessel is to contain
the melt or molten material within melt zone.
Embodiments relate to apparatus and methods to control the position
and shape of molten feedstock in an inline melting apparatus, a
coil operating at a lower frequency than the main helical melt coil
and positioned near the end of the melt coil is used to exert a
force on molten alloy contained within the latter. The Laplace
forces generated by the "containment" coil act against those
generated by the melt coil (which tend to push the alloy out)
without substantially reducing the inductive heating of the alloy.
This allows the alloy to be melted and controllably introduced into
another system such as a cold chamber die caster for subsequent
forming. The advantages of the apparatus and method would be to
allow the alloy to be electromagnetically contained without using a
physical obstruction to contain the alloy.
FIGS. 2A to 2D shows various embodiments of the apparatus. The
apparatus could comprise a vessel configured to receive a material
such as an ingot shown in FIGS. 2A to 2D for melting therein. Shown
in the embodiments are a first induction coil, configured to melt
the material therein; and a second induction coil, positioned in
line with the first induction coil, wherein the second induction
coil or a combination of the first induction coil and the second
induction coil is configured to function as a gate or a valve for
containing movement of the molten material in a horizontal
direction within the vessel. In one embodiment, the first induction
coil is a load or heating coil and the second induction coil is a
containing coil. Alternatively, in another embodiment, the first
induction coil is a containing coil and the second induction coil
is a heating coil. The heating induction coil can be used to tune
the frequency to maximize thermal energy generation on a meltable
material (e.g., in the form of an ingot). The containing induction
coil can be used to tune the frequency to maximize forces applied
to the melt.
For explanatory purposes only, it should be understood that FIGS.
2A-2D reference injection of molten material into a mold in a
horizontal direction, out of a vessel, from right to left.
Accordingly, in these illustrative embodiments, first induction
coil is a heating coil and second induction coil is a containing
coil. However, the direction of movement and the heating/containing
coil assignments are not meant to be limiting.
In any of these embodiments, the material for melting could
comprise a BMG feedstock, and the apparatus is configured to mold
the material into a BMG part.
In two exemplary embodiments, the first induction coil and the
second induction coil are part of a single induction coil (shown in
FIG. 2B) or two distinct induction coils (shown in FIG. 2A). The
coils are used to control the melt via RF power. For example, the
second coil (e.g., containment coil) may be provided on the left
and the first coil (e.g., heating coil) on the right. They can be
connected and configured to operate at the same frequency.
Accordingly, FIG. 2B shows a coil configuration that performs both
heating and containment functions. In operation, the melt
temperature and stifling remains relatively uniform in the region
between the first and second coils.
The frequencies of the first and second induction coils may be
different. If using a single coil to perform both functions, i.e.,
heating and containing, then only one frequency may run. This
results in a selected frequency that is a compromise between the
frequencies for heating the material and for optimizing force
applied to the melt. In accordance with an embodiment, the first
induction coil and the second induction coil are part of a single
induction coil having an electrical tap (shown in FIG. 2C) therein
configured to independently control the first induction coil and
the second induction coil. The electrical tap allows independent
control of either or both coils, so that the magnetic field can be
rapidly changed. In an embodiment wherein a first and second
induction coil are part of a single coil, the electrical tap can
allow control of at least one portion or one side of the single
coil.
Optionally, one or both of the first induction coil and the second
induction coil could comprise a taper shape or cylindrical shape in
FIGS. 2A-2D.
The second induction coil could be wrapped around the first
induction coil as or vice-versa as shown in FIG. 2D. FIG. 2D shows
one example, in accordance with an embodiment, of de-coupling the
first (e.g., heating) and second (e.g., containing) induction
coils, where the second coil uses similar principles described
above. The first and second induction coils may have different
frequencies. For example, the second induction coil could generally
have a lower RF frequency than the first induction coil.
Also, during melting of meltable material, it is also envisioned
that a plunger of the system (e.g., plunger rod 330 of system 300)
may be configured to assist in containing the meltable material
within a vessel. For example, in an embodiment wherein a plunger is
configured to move in a horizontal direction from right to left to
inject the material into a mold (thus ejecting the molten material
from the vessel), the plunger may be positioned to contain a melt
from a right side (adjacent to first induction coil) to keep molten
material from being ejected out the wrong side. The coil
configuration may be designed to contain the melt on the opposite
side leading to the mold (left side). In an embodiment, the plunger
may be used in with and/or in addition to any of the coil
configurations shown in FIG. 2A, 2B, 2C, or 2D.
In an embodiment, the meltable material is contained on its bottom
by a water-cooled boat, vessel, or container, that may or may not
comprise with a substantially U-shaped channel.
The vessel (not shown in FIGS. 2A to 2D, but instead an ingot
within the vessel is shown) could be positioned along a horizontal
axis of the first induction coil or the second induction such that
movement of the material in the vessel is in a horizontal direction
along an ejection path of the vessel. The second induction coil
could be positioned near an ejection end of the vessel, for
example, shown in FIG. 2B.
The apparatus could further comprise an additional induction coil
located at either an ejection end of the vessel or an opposite side
of the ejection end of the vessel. An additional induction coil is
not shown in FIGS. 2A to 2D. The vessel could further comprise one
or more temperature regulating channels (not shown in FIGS. 2A to
2D) configured to flow a fluid therein for regulating a temperature
of the vessel during melting of the material. The apparatus further
comprise a mold (not shown in FIGS. 2A to 2D) configured to receive
the melt from the vessel and to mold the melt into the BMG part. In
FIGS. 2A to 2D, the second induction coil or the combination of the
first induction coil and the second induction coil is configured to
function as a valve to control movement of the melt from the vessel
through an injection path to the mold (not shown in FIGS. 2A to
2D).
In accordance with various embodiments, there is provided an
apparatus. The apparatus may include a vessel configured to receive
a material for melting therein; a load induction coil positioned
adjacent to the vessel to melt the material therein; and a
containment induction coil positioned in line with the load
induction coil. The containment induction coil is configured to
contain the melt within the load induction coil.
In accordance with various embodiments, there is provided a melting
method using an apparatus. The apparatus may include a vessel
configured to receive a material for melting therein; a load
induction coil positioned adjacent to the vessel to melt the
material therein; and a containment induction coil positioned in
line with the load induction coil. The material in the vessel can
be heated by operating the load induction coil at a first RF
frequency to form a molten material. While the melt is heated
and/or maintained at desired temperature, the containment induction
coil can be operated at a second RF frequency to contain the molten
material within the load induction coil.
In accordance with various embodiments, there is provided a melting
method using an apparatus. The apparatus may include a vessel
configured to receive a material for melting therein; a load
induction coil positioned adjacent to the vessel to melt the
material therein; and a containment induction coil positioned in
line with the load induction coil. The material in the vessel can
be heated by operating the load induction coil at a first RF
frequency to form a molten material. While heating, the containment
induction coil can be operated at a second RF frequency to contain
the molten material within the load induction coil. Once the
desired temperature is achieved and maintained for the molten
material, operation of the containment induction coil can be
stopped and the molten material can be ejected from the vessel into
a mold through an ejection path.
The methods, techniques, and devices illustrated herein are not
intended to be limited to the illustrated embodiments. As disclosed
herein, an apparatus or a system (or a device or a machine) is
configured to perform melting of and injection molding of
material(s) (such as amorphous alloys). The apparatus is configured
to process such materials or alloys by melting at higher melting
temperatures before injecting the molten material into a mold for
molding. As further described below, parts of the apparatus are
positioned in-line with each other. In accordance with some
embodiments, parts of the apparatus (or access thereto) are aligned
on a horizontal axis. The following embodiments are for
illustrative purposes only and are not meant to be limiting.
FIG. 3 illustrates a schematic diagram of such an exemplary
apparatus. More specifically, FIG. 3 illustrates an injection
molding apparatus 300. In accordance with an embodiment, injection
molding system 300 can include a melt zone 310 configured to melt
meltable material 305 received therein, and at least one plunger
rod 330 configured to eject molten material 305 from melt zone 310
and into a mold 340. In an embodiment, at least plunger rod 330 and
melt zone 310 are provided in-line and on a horizontal axis (e.g.,
X axis), such that plunger rod 330 is moved in a horizontal
direction (e.g., along the X-axis) substantially through melt zone
310 to move the molten material 305 into mold 340. The mold can be
positioned adjacent to the melt zone.
The meltable material can be received in the melt zone in any
number of forms. For example, the meltable material may be provided
into melt zone 310 in the form of an ingot (solid state), a
semi-solid state, a slurry that is preheated, powder, pellets, etc.
In some embodiments, a loading port (such as the illustrated
example of an ingot loading port 318) may be provided as part of
injection molding apparatus 300. Loading port 318 can be a separate
opening or area that is provided within the machine at any number
of places. In an embodiment, loading port 318 may be a pathway
through one or more parts of the machine. For example, the material
(e.g., ingot) may be inserted in a horizontal direction into the
vessel 312 by plunger 330, or may be inserted in a horizontal
direction from the mold side of the injection apparatus 300 (e.g.,
through mold 340 and/or through a transfer sleeve 350 into vessel
312). In other embodiments, the meltable material can be provided
into melt zone 310 in other manners and/or using other devices
(e.g., through an opposite end of the injection apparatus).
Melt zone 310 includes a melting mechanism configured to receive
meltable material and to hold the material as it is heated to a
molten state. The melting mechanism may be in the form of a vessel
312, for example, that has a body for receiving meltable material
and configured to melt the material therein. A vessel as used
throughout this disclosure is a container made of a material
employed for heating substances to high temperatures. For example,
in an embodiment, the vessel may be a crucible, such as a boat
style crucible, or a skull crucible. In an embodiment, vessel 312
is a cold hearth melting device that is configured to be utilized
for meltable material(s) while under a vacuum (e.g., applied by a
vacuum device or pump at a vacuum port 332). In one embodiment,
described further below, the vessel is a temperature regulated
vessel.
Vessel 312 may also have an inlet for inputting material (e.g.,
feedstock) into a receiving or melting portion 314 of its body. In
the embodiments shown in the Figures, the body of vessel 312 may
include a substantially U-shaped structure. However, this
illustrated shape is not meant to be limiting. Vessel 312 can
include any number of shapes or configurations. The body of the
vessel has a length and can extend in a longitudinal and horizontal
direction, such that molten material is removed horizontally
therefrom using plunger 330. For example, the body may include a
base with side walls extending vertically therefrom. The material
for heating or melting may be received in a melting portion 314 of
the vessel. Melting portion 314 is configured to receive meltable
material to be melted therein. For example, melting portion 314 has
a surface for receiving material. Vessel 312 may receive material
(e.g., in the form of an ingot) in its melting portion 314 using
one or more devices of an injection apparatus for delivery (e.g.,
loading port and plunger).
In an embodiment, body and/or its melting portion 314 may include
substantially rounded and/or smooth surfaces. For example, a
surface of melting portion 314 may be formed in an arc shape.
However, the shape and/or surfaces of the body are not meant to be
limiting. The body may be an integral structure, or formed from
separate parts that are joined or machined together. The body of
vessel 312 may be formed from any number of materials (e.g.,
copper, silver), include one or more coatings, and/or
configurations or designs. For example, one or more surfaces may
have recesses or grooves therein.
The body of vessel 312 may be configured to receive the plunger rod
there-through in a horizontal direction to move the molten
material. That is, in an embodiment, the melting mechanism is on
the same axis as the plunger rod, and the body can be configured
and/or sized to receive at least part of the plunger rod. Thus,
plunger rod 330 can be configured to move molten material (after
heating/melting) from the vessel by moving substantially through
vessel 312, and into mold 340. Referencing the illustrated
embodiment of apparatus 300 in FIG. 3, for example, plunger rod 330
would move in a horizontal direction from the right towards the
left, through vessel 312, moving and pushing the molten material
towards and into mold 340.
To heat melt zone 310 and melt the meltable material received in
vessel 312, injection apparatus 300 also includes a heat source
that is used to heat and melt the meltable material.
At least melting portion 314 of the vessel, if not substantially
the entire body itself, is configured to be heated such that the
material received therein is melted. Heating is accomplished using,
for example, an induction source 320L positioned within melt zone
310 that is configured to melt the meltable material. In an
embodiment, induction source 320L is positioned adjacent vessel
312. For example, induction source 320L may be in the form of a
coil positioned in a helical pattern substantially around a length
of the vessel body. Accordingly, vessel 312 may be configured to
inductively melt a meltable material (e.g., an inserted ingot)
within melting portion 314 by supplying power to induction
source/coil 320L, using a power supply or source 325. Thus, the
melt zone 310 can include an induction zone. Induction coil 320L is
configured to heat up and melt any material that is contained by
vessel 312 without melting and wetting vessel 312. Induction coil
320L emits radiofrequency (RF) waves towards vessel 312. As shown,
the body and coil 320L surrounding vessel 312 may be configured to
be positioned in a horizontal direction along a horizontal axis
(e.g., X axis).
In one embodiment, the vessel 312 is a temperature regulated
vessel. Such a vessel may include one or more temperature
regulating channels configured to flow a gas or a liquid (e.g.,
water, oil, or other fluid) therein for regulating a temperature of
the body of vessel 312 during melting of material received in the
vessel (e.g., to force cool the vessel). Such a forced-cool
crucible can also be provided on the same axis as the plunger rod.
The cooling channel(s) can assist in preventing excessive heating
and melting of the body of the vessel 312 itself. Cooling
channel(s) may be connected to a cooling system configured to
induce flow of a gas or a liquid in the vessel. The cooling
channel(s) may include one or more inlets and outlets for the fluid
to flow there-through. The inlets and outlets of the cooling
channels may be configured in any number of ways and are not meant
to be limited. For example, cooling channel(s) may be positioned
relative to melting portion 314 such that material thereon is
melted and the vessel temperature is regulated (i.e., heat is
absorbed, and the vessel is cooled). The number, positioning and/or
direction of the cooling channel(s) should not be limited. The
cooling liquid or fluid may be configured to flow through the
cooling channel(s) during melting of the meltable material, when
induction source 320L is powered.
After the material is melted in the vessel 312, plunger 330 may be
used to force the molten material from the vessel 312 and into a
mold 340 for molding into an object, a part or a piece. In
instances wherein the meltable material is an alloy, such as an
amorphous alloy, the mold 340 is configured to form a molded bulk
amorphous alloy object, part, or piece. Mold 340 has an inlet for
receiving molten material there-through. An output of the vessel
312 and an inlet of the mold 340 can be provided in-line and on a
horizontal axis such that plunger rod 330 is moved in a horizontal
direction through body 22 of the vessel to eject molten material
and into the mold 340 via its inlet.
As previously noted, systems such as injection molding system 300
that are used to mold materials such as metals or alloys may
implement a vacuum when forcing molten material into a mold or die
cavity. Injection molding system 300 can further includes at least
one vacuum source or pump that is configured to apply vacuum
pressure to at least melt zone 310 and mold 340 at vacuum ports
312. The vacuum pressure may be applied to at least the parts of
the injection molding system 300 used to melt, move or transfer,
and mold the material therein. For example, the vessel 312,
transfer sleeve 350, and plunger rod 330 may all be under vacuum
pressure and/or enclosed in a vacuum chamber.
In an embodiment, mold 340 is a vacuum mold that is an enclosed
structure configured to regulate vacuum pressure therein when
molding materials. For example, in an embodiment, vacuum mold 340
includes a first plate (also referred to as an "A" mold or "A"
plate), a second plate (also referred to as a "B" mold or "B"
plate) positioned adjacently (respectively) with respect to each
other. The first plate and second plate generally each have a mold
cavity associated therewith for molding melted material
there-between. The cavities are configured to mold molten material
received there-between via an injection sleeve or transfer sleeve
350. The mold cavities may include a part cavity for forming and
molding a part therein.
Generally, the first plate may be connected to transfer sleeve 350.
In accordance with an embodiment, plunger rod 330 is configured to
move molten material from vessel 312, through a transfer sleeve
350, and into mold 340. Transfer sleeve 350 (sometimes referred to
as a shot sleeve, a cold sleeve or an injection sleeve in the art
and herein) may be provided between melt zone 310 and mold 340.
Transfer sleeve 350 has an opening that is configured to receive
and allow transfer of the molten material there-through and into
mold 340 (using plunger 330). Its opening may be provided in a
horizontal direction along the horizontal axis (e.g., X axis). The
transfer sleeve need not be a cold chamber. In an embodiment, at
least plunger rod 330, vessel 312 (e.g., its receiving or melting
portion), and opening of the transfer sleeve 350 are provided
in-line and on a horizontal axis, such that plunger rod 330 can be
moved in a horizontal direction through vessel 312 in order to move
the molten material into (and subsequently through) the opening of
transfer sleeve 350.
Molten material is pushed in a horizontal direction through
transfer sleeve 350 and into the mold cavity(ies) via the inlet
(e.g., in a first plate) and between the first and second plates.
During molding of the material, the at least first and second
plates are configured to substantially eliminate exposure of the
material (e.g., amorphous alloy) there-between, e.g., to oxygen and
nitrogen. Specifically, a vacuum is applied such that atmospheric
air is substantially eliminated from within the plates and their
cavities. A vacuum pressure is applied to an inside of vacuum mold
340 using at least one vacuum source that is connected via vacuum
lines 332. For example, the vacuum pressure or level on the system
can be held between 1.times.10.sup.-1 to 1.times.10.sup.-4 Torr
during the melting and subsequent molding cycle. In another
embodiment, the vacuum level is maintained between
1.times.10.sup.-2 to about 1.times.10.sup.-4 Torr during the
melting and molding process. Of course, other pressure levels or
ranges may be used, such as 1.times.10.sup.-9 Torr to about
1.times.10.sup.-3 Torr, and/or 1.times.10.sup.-3 Torr to about 0.1
Torr. An ejector mechanism (not shown) is configured to eject
molded (amorphous alloy) material (or the molded part) from the
mold cavity between the first and second plates of mold 340. The
ejection mechanism is associated with or connected to an actuation
mechanism (not shown) that is configured to be actuated in order to
eject the molded material or part (e.g., after first and second
parts and are moved horizontally and relatively away from each
other, after vacuum pressure between at least the plates is
released).
Any number or types of molds may be employed in the apparatus 300.
For example, any number of plates may be provided between and/or
adjacent the first and second plates to form the mold. Molds known
in the art as "A" series, "B" series, and/or "X" series molds, for
example, may be implemented in injection molding system/apparatus
300.
A uniform heating of the material to be melted and maintenance of
temperature of molten material in such an injection molding
apparatus 300 assists in forming a uniform molded part. For
explanatory purposes only, throughout this disclosure material to
be melted is described and illustrated as being in the form of an
ingot 305 that is in the form of a solid state feedstock; however,
it should be noted that the material to be melted may be received
in the injection molding system or apparatus 300 in a solid state,
a semi-solid state, a slurry that is preheated, powder, pellets,
etc., and that the form of the material is not limiting. In
addition, the illustrated view of vessel 312 is a cross-sectional
view taken along X-axis of a U-shaped boat/vessel for illustrative
purposes only.
In an injection molding apparatus that is positioned inline and in
a horizontal direction and to get the most power input into the
material for melting, containing the material in the melt zone,
adjacent to induction coil, is effective for a consistent melt
cycle, rather than, for example, having molten material flow
towards and/or out of the ejection path of the vessel.
FIG. 4 depicts a current injection molding system configured having
one induction coil 420. The coil 420 may impose forces on the
material 405 for melting, e.g., metals/metal alloys, placed inside
the vessel 410, and ultimately, when the material 405 is molten,
the induction coil 420 imposes forces on the molten material 405
within the coil 420. These forces may act to squeeze the molten
material inwards to the center of the vessel, as shown. Meanwhile,
these forces may push the molten material 405 out of the induction
coil 420 e.g., at the ends of the induction coil 420, while the
molten material is being smoothed out during heating by the
induction coil.
As disclosed herein, the exemplary injection molding
apparatus/system 300 in FIG. 3 includes a plurality of separate
induction coils, such as, for example, a load induction coil 320L
and a containment induction coil 320C.
In embodiments, the induction coils 320L and 320C can emit
radiofrequency (RF) waves towards the vessel 312. The coils 320L
and 320C may or may not be tapered. The coils 320L and 320C may
include, e.g., spherical coil. In embodiments, the coils may have
the same or different shapes such that the generated RF fields can
be tuned, e.g., be more directional as desired. For example, the
containment induction coil 320C can be taper-shaped or cone-shaped
coil, with the wide region spacing from, facing, the load induction
coil 320L. By using the tuned RF fields, stronger forces can be
generated by the containment induction coil 320C and imposed to the
melt toward the load induction coil 320L. The melt/molten material
can then be contained within the load induction coil 320L.
The containment induction coil 320C can be spaced apart but
configured in line with the load induction coil 320L. The
containment induction coil 320C can be configured near the ejection
end of the melting zone 310. The load induction coil 320L can be
configured for heating/melting the material 305 for melting placed
in the melting portion 314 of the vessel 310. The containment
induction coil 320C can be configured for positioning and/or
containing the melt or molten material within the load induction
coil 320L during the heating/melting process. The containment
induction coil 320C can prevent the melt or the molten material
from flowing out of the load induction coil 320L and the material
305 in the vessel 312 can remain heated and molten. Likewise, the
melt/molten material can be contained within the melt zone 310 of
the apparatus/system 300 while it's being smoothed out and minimize
heat loss.
In embodiments, the containment induction coil 320C and the load
induction coil 320L can be operated at different frequencies in
order to position/contain the melt, e.g., at melting temperatures.
For example, the load induction coil 320L for heating/melting the
meltable materials can operate at one frequency f.sub.melting,
while the containment induction coil 320C for containing the
melt/molten material can operate at a different frequency
f.sub.containment. In embodiments, f.sub.melting, may be greater
than f.sub.containment. The containment induction coil 320C
operating at a lower frequency may generate a stronger net force on
the melt/molten material. The containment induction coil 320C may
impose such force, e.g., Laplace forces, on the melt, to act
against those generated by the load induction coil (which tend to
push the melt out) and push the melt back to be contained within
the load induction coil 320L.
The containment induction coil 320C and the load induction coil
320L are spaced apart and operated out of sync in frequencies. The
magnetic fields generated by the coils 320C and 320L do not
necessarily cancel out (although they may otherwise interact) with
one another. In general, when two coils have coil turns, e.g.,
helical turns, in reversed or opposite directions, the magnetic
fields generated may oppose to and cancel out with one another. In
such region where the opposing turns are in effect, the materials
to be melted cannot be heated and may tend to freeze onto the
vessel due to cancellation of the magnetic fields.
As disclosed herein, by controlling frequencies, powers,
interaction between magnetic fields, etc. of one or both of the
load induction coil 320C and the containment induction coil 320,
the materials 305 in the vessel 312 can be heated/melted and
further contained within the load induction coil 320C.
In embodiments, the containment induction coil 320c can be
energized or de-energized as needed to function as a gate or a
valve in the ejection path of the melt from the vessel 312 to the
mold 340 and/or to control movement of the melt in the ejection
path into the mold 340. For example, when the material 305 is
heated/melted by operating the load induction coil 320L, by turning
on the containment induction coil 320C the heated material/melt can
be contained within the load induction coil 320L; by turning off
the containment induction coil 320C, the melt can be ejected from
or pushed out of the load induction coil 320L; and/or by turning
the containment induction coil 320C back on, e.g., as a portion of
the melt passed the "gate region" or the ejection end of the vessel
312, this portion of the melt can keep moving through the transfer
sleeve (e.g., a cold sleeve or a shot sleeve) of the mold 340,
while the melt portion within the load induction coil 320L can be
contained.
In this manner, the vessel 312 is positioned along a horizontal
axis (X-axis) such that the movement of the molten material/melt
can be in a horizontal direction when directed through the ejection
path (e.g., using plunger 330). Surrounding at least part of vessel
312 is load induction coil 320L, and surrounding at least part of
the vessel 312 near the ejection end of the vessel 312 is the
containment induction coil 320C, such that materials are
heated/melted by the load induction coil 320L and contained within
the load induction coil 320L.
In embodiments, as shown in FIG. 5, a second containment induction
coil 320C2 can be configured in line with the load induction coil
320L at an opposite end of the containment induction coil 320C1,
i.e., at an opposite side of the injection path. The first and
second containment induction coil 320C1-C2 may be the same or
different and may be controlled to have the same or different
functions. In this manner, the melt 305 in the vessel 312 can be
contained within the load induction coil 320L from both ends
thereof.
In embodiments, when utilizing BMG as the material in the injection
molding apparatus 300/500, articles/parts with a high elastic
limit, corrosion resistance, and low density can be formed.
FIG. 6 illustrates a method 600 for melting material and/or molding
a part in accordance with an embodiment of the disclosure using
apparatus 300 and/or 500, as shown in FIGS. 3 and 5, although the
apparatus and methods disclosed herein are not limiting with one
another in any manner.
At block 610 of FIG. 6, an apparatus is designed to include, for
example, a vessel 312 configured to receive a material 305 for
melting therein, a load induction coil 320L positioned adjacent the
vessel to melt the material 305 therein; and a containment
induction coil 320C positioned in line with the load induction
coil. Generally, the injection molding apparatus 300/500 may be
operated in the following manner: materials for melting 305 (e.g.,
amorphous alloy or BMG in the form of a single ingot) can be loaded
into a feed mechanism (e.g., loading port 318), inserted and
received into the melt zone 310 into the vessel 312 (surrounded by
the load induction coil 320L). The injection molding machine
"nozzle" stroke or plunger 330 can be used to move the material, as
needed, into the melting portion 314 of the vessel 312.
At block 620, the material 305 for melting can be heated through
the induction process, e.g., by supplying power via a power source
325L to the load induction coil 320L. During heating/melting, a
cooling system can be activated to flow a (cooling) fluid in any
cooling channel(s) 316 of the vessel 312. The injection molding
machine controls the temperature through a closed or opened loop
system, which will stabilize the material 305 at a specific
temperature (e.g., using a temperature sensor and a
controller).
At block 630, the containment induction coil 320C can be operated
at a RF frequency lower than the load induction coil 320L to
control the position and shape of the molten material or molten
feedstock in the inline melting apparatus. The containment
induction coil 320C may exert a force, e.g., Laplace forces, on the
molten material, acting against those generated by the load
induction coil (which tends to push the molten material out)
without substantially reducing the inductive heating of the molten
material 305.
At block 640, once the desired temperature is achieved and
maintained for the melt in the vessel 312, the ejection path of the
vessel 312 can be "opened" by turning off the containment induction
coil 320C such that the melt/molten material can be subsequently
ejected from the vessel into a mold 340 through an ejection path,
e.g., the transfer sleeve 350, e.g., as seen at block 650 of FIG.
6. The mold 340 can be any mold in a caster such as a cold chamber
die. The ejection can be performed in a horizontal direction (e.g.,
from right to left as shown in FIGS. 3 and 5) along the horizontal
axis (X axis). This may be controlled using plunger 330, which can
be activated, e.g., using a servo-driven drive or a hydraulic
drive. The mold 340 is configured to receive molten material
through an inlet and configured to mold the molten material under
vacuum, for example. That is, the molten material is injected into
an evacuated cavity between the at least first and second plates to
mold the part in the mold 340. As previously noted, in some
embodiments, the material may be an amorphous alloy material that
is used to mold a bulk amorphous alloy part. Once the mold cavity
has begun to fill, pressure (via the plunger) can be held at a
given level to "pack" the molten material into the remaining void
regions within the mold cavity and mold the material. After the
molding process (e.g., approximately 10 to 15 seconds), the vacuum
applied to at least the mold 340 (if not the entire apparatus
300/500) can be released. Mold 340 is then opened and the
solidified part is exposed to the atmosphere. In embodiments, an
ejector mechanism is actuated to eject the solidified, molded
object from between the at least first and second plates of mold
340 via an actuation device (not shown). Thereafter, the process
can begin again. Mold 340 can then be closed by moving at least the
at least first and second plates relative to and towards each other
such that the first and second plates are adjacent each other. The
melt zone 310 and mold 340 is evacuated via the vacuum source once
the plunger 330 has moved back into a load position, in order to
insert and melt more material and mold another part.
Although not described in great detail, the disclosed injection
system may include additional parts including, but not limited to,
one or more sensors, flow meters, etc. (e.g., to monitor
temperature, cooling water flow, etc.), and/or one or more
controllers. The material to be molded (and/or melted) using any of
the embodiments of the injection system as disclosed herein may
include any number of materials and should not be limited. In one
embodiment, the material to be molded is an amorphous alloy, as
described above.
Applications of Embodiments
The presently described apparatus and methods can be used to form
various parts or articles, which can be used, for example, for
Yankee dryer rolls; automotive and diesel engine piston rings; pump
components such as shafts, sleeves, seals, impellers, casing areas,
plungers; Wankel engine components such as housing, end plate; and
machine elements such as cylinder liners, pistons, valve stems and
hydraulic rams. In embodiments, apparatus and methods can be used
to form housings or other parts of an electronic device, such as,
for example, a part of the housing or casing of the device or an
electrical interconnector thereof. The apparatus and methods can
also be used to manufacture portions of any consumer electronic
device, such as cell phones, desktop computers, laptop computers,
and/or portable music players. As used herein, an "electronic
device" can refer to any electronic device, such as consumer
electronic device. For example, it can be a telephone, such as a
cell phone, and/or a land-line phone, or any communication device,
such as a smart phone, including, for example an iPhone.TM., and an
electronic email sending/receiving device. It can be a part of a
display, such as a digital display, a TV monitor, an
electronic-book reader, a portable web-browser (e.g., iPad.TM.),
and a computer monitor. It can also be an entertainment device,
including a portable DVD player, DVD player, Blu-Ray disk player,
video game console, music player, such as a portable music player
(e.g., iPod.TM.), etc. It can also be a part of a device that
provides control, such as controlling the streaming of images,
videos, sounds (e.g., Apple TV.TM.), or it can be a remote control
for an electronic device. It can be a part of a computer or its
accessories, such as the hard driver tower housing or casing,
laptop housing, laptop keyboard, laptop track pad, desktop
keyboard, mouse, and speaker. The coating can also be applied to a
device such as a watch or a clock.
While the invention is described and illustrated here in the
context of a limited number of embodiments, the invention may be
embodied in many forms without departing from the spirit of the
essential characteristics of the invention. The illustrated and
described embodiments, including what is described in the abstract
of the disclosure, are therefore to be considered in all respects
as illustrative and not restrictive. The scope of the invention is
indicated by the appended claims rather than by the foregoing
description, and all changes that come within the meaning and range
of equivalency of the claims are intended to be embraced
therein.
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